Apparatus for forming sheet metal forms



Jan. 10, 1939.

J. L. AUBLE APPARATUS FOR FORMING SHEET METAL FORMS I Filed Oct. 14,1956 4 Sheets-Sheet l 2 I z 1 F //%fig 53 [3 230 I C 30 o 23h 5 40 3323a 42 L 38 g Q :19 22: B 2.9 o 55 41 22 51 37 o 20 A 23 o o Ell-1.1.

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Jan. 10, 1939. AUBL; 2,143,429

APPARATUS FOR FORMING SHEET METAL FORMS Filed Oct. 1 4, 1936 4 SheetsSheet 2 42 52 42 23 o 55. 41a 6 o 4/ a O a :4 wk 4 l0 9 Z I 2 5 1 P l N g IINVENTOR. J4M5 L. flue/.5.

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Jan. 10; 1939. J. L. AUBLE 2,143,429

APPARATUS FOR FORMING SHEET METAL FORMS Filed Oct 14, 1956 4Sheets-Sheet 3 INVENTOR. 63.3 JAMES [1.AUBLE.

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J. L. AUBLE APPARATUS FOR FORMING SHEET METAL FORMS Filed Oct. 14, less4-,Sheets-Sheet 4 Jan. 10, 1939.

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ATTORN Patented Jan. 10, 1939 PATENT OFFICE 2,143,429 APPARATUS FORFORMING SHEET LIETAL FORMS James. L. Auble, Cincinnati, Ohio, assignorto Frank Tea & Spice Company, Cincinnati, Ohio,

a corporation of Ohio Application October 14, 1936, Serial No. 105,550

2 Claims.

My invention relates to theart of drawing and forming sheet metal intoforms by a series of forming operations without removing the piece beingformed from the drawing and forming means.

This application is a continuation in part of my copending applicationSerial No. 68,904, filed March 14, 1936, and entitled Apparatus for andmethod of forming sheet metal forms.

The forming of sheet metal in various forms by the pressure against asheet of metal by a multiple telescoping die, is not new. Such anarrangement is suggested in the patent to Schimmelbusch No, 783,390. Inmy Patent No, 1,919,287, of July 25, 1933, mechanism is illustratedwhich also operates on the above-noted principle. My invention relatesto improvements in such forming mechanism in which the tendencies of themetal sheet to buckle and flow unevenly are avoided.

In the forming of sheet metal in mechanism such as that to which myinvention relates, the' pressure of a die is applied against the sheetwhich forces the metal into a female die or mold. If the sheet is heldwith a fixed clamping action, the difliculty of adjusting the tensionmakes it likely that the sheet is either held too firmly, in

which event the metal actually contacted by the die will be drawn outtoo thin, or if the sheet is not held firmly enough, the complete sheetwill be pressed, without sufficient drawing of the metal into the femalemould, and with the metal lation to the movements necessary to completethe forming operation, in which the frictional retarding action on thesheet being formed is pneumatically controlled.

Because of the pneumatic control of the frictional sheet holdingdevices, I am' enabled to draw and form metal forms in which the actionof the male forming die and the female die is a direct reciprocatingaction, without any relative rotative movement of the various parts OIthe dies with relation one to another.

In my Patent No. 1,919,287, there is disclosed a forming mechanism forsheet metal forms having telescoping rotative parts which act insequence and position themselves so as to permit the formation of theobjectsformed in sequential operations without removing the piece fromthe forming device until it has been completely formed. While suchmechanism is effective, the movement of the parts of the male diemechanism requires a worm actuating drive. In my present invention, astraight reciprocating movement, such as can be brought about in anordinary toggle press, replaces the old worm drive action, and thispermits much greater speed of operation. Further, the pneumaticfrictional holding back of the metal sheet permits sufiicient slippa eto cause the metal to flow evenly.

Because of the pneumatic control of the frictional holding of the metalplate during the forming operation, a greater adjustability controllingthe flow of the metal is permitted, simply by a variation in the airpressure with which the friction clamping plates are actuated.

The above objects and other objects to which reference will be made inthe ensuing disclosure, I accomplish by that certain combination andarrangement of parts of which I have illustrated a preferred embodiment.

Referring to the drawings:

Figure 1 is a vertical sectional view with some parts diagrammaticallyindicated, of the forming apparatus mounted on a toggle press.

Fig. 2 is a bottom plan view of a portion of one of the latching devicesillustrated in Fig, 1.

Fig, 3 is a sectional view of the parts of the mechanism, after thefirst stage of the forming operation.

Fig. 4 is a vertical sectional view of the parts after the third stageof the forming operation.

Fig. 5 is a bottom plan view of the male die assembly illustrated inFig. 1, taken from the position indicated by the arrows 5, 5.

Fig. 6 is a perspective view of a sheet metal plate after the firstforming operation.

Fig. 7 is a perspective view of the sheet metal plate after the secondforming operation.

Fig. 8 is a perspective view of a sheet metal form after the thirdforming operation.

Fig. 9 isa perspective view of the final form of the sheet metal object.

Fig. 10 is a vertical sectional view of a slightly modified form ofapparatus showing details from which the plan of operation will bereadily understood.

Fig. 11 is a detail view of the cam track shown in Fig. 10.

Fig. 12 is a horizontal sectional view of the valves employed in theapparatus shown in Fig. 10.

- Fig. 13 is a horizontal sectional view of the valve shown in Fig. 12in open position.

Referring to the drawings, the upper head of the press is indicated as aplaten secured to the actuating parts of the press by means of bolts 2.The female die elements are mounted on the lower platen or base plate 3of the press.

The female die 4, illustrated in Fig. 1, is secured to the base plate 3by means of bolts 5. The shape of the female die is as indicated. Thefirst stage opening has inwardly curving walls 6, and a downwardlyextending annular wall I.

An inwardly beveled annular portion 8 connects with the second stage dieopening, which has a downwardly depending annular wall 9. Anotherinwardly inclining ledge |0 forms a continuous wall with the third stagefemale die opening Still another inwardly inclined ledge l2 connects thewall continuously with the final stage female die opening I 3, in whichthe final shape of the drawn and formed article is accomplished.

An opening M in the base plate 3 permits the upward passage of theejector ram |5, which, after the article is formed. ejects it upwardlyand outwardly from the female die.

Extending upwardly from and threaded into the die 4, is the latch guidebar l6. Further mounted ,on the base plate is the bracket H, whichcarries the cam track member l8, which, at proper intervals in thedrawing and forming operation, cuts ofi the air from the frictionalclamping plates.

The upper platen carries a head l9, having a cylindrical inner wall 20.Within the cylinder 20 are the cylinder heads 2|, 22 and 23. Thecylinder heads retain compression within the cylinder because of annularwashers 2|a, 22a and 23a. held in position by annular rings 2|b, 22b,and 23b. The cylinder heads carry the concentrically mounted male diemembers 24, 25, and 26. These dies telescope one within the otherinversely in the relation in which they have been referred to, and themain male ram 21 is reciprocated in the opening within the inner maledie member 26.

Compression cylinders A, B, and C are formed in which air enters throughports 28, 29 and 30. Valves 5|, 52 and 53, having rocking actuating arms54, 55 and 56, control the release of air through ports 28, 29 and 30.The heads 22 and 23 which respectively carry the male die members 24 and25, are retained in their relative position with relation .to the headI, by means of the difference in the air pressure in the differentchambers, as will be later explained. The heads are locked againstreceding movement, by means of a series of latch members 31, 38 whichare normally pressed inwardly by means of springs 39, 40.

As will be subsequently described, during the operation of themechanism, after the heads 22 and 23 have completed their initialdownward strokes and the compressed gas in the cylinders which haveactuated them is exhausted, the latches are released by means of'triggerarms 4|, 42, which engage the member l6, the trigger 4| being actuatedat the bottom of the cam surface of the member l6, in the positionindicated at Ma, while the trigger 42 is actuated in a position on thecam surfaceindicated at 42 As best shown in Fig. 10, the valves 3|, 32,33 are connected by means of the flexible tubes 3la, 32a, 33a topressure reducing valves 3|b, 32b, 33b. These reducing and regulatingvalves are supplied with compressed gas from a pressure main 3|c havinga source of gas under pressure such as the pressure tank 3|d.

The valves 3|, 32, and 33 are normally open so that pressure of, forexample, 60 to lbs. exist in cylinder A, 40 to -60 lbs. in cylinder Band 10 to 40 lbs. in cylinder C.

The structure of the valves 3|, 32 and 33 is best shown in Figs. 12 and13. Fig. 12 shows the valve open in the position in which air isexhausted from the cylinders. Fig. 13 shows the valve closed in whichposition the pressure automatically controlled by the regulating valves3|b, 32b, and 33b is permitted to flow to the respective cylinders.

Explaining the structure and operation of one of these relief valves,the valve, the casing of which is illustrated at 3| has an outletp0I't3Ie, an inlet port 3|) and a pressure relief port 3| g. A valvestem 3|h has an intake valve disc 3li, and a release valve disc 3|7'which discs seat and close the ports 3| f and 3|g respectively. A spring3| k urges the valve disc 3|z against its seat. A plunger 3|l has arounded exposed end which abuts a set screw 3|m which extends through apivoted arm 34, which carries on its free end a cam roller 3l0. A spring3|p exerts a pull on the arm 3|n sufiicient to overcome the pressure ofthe spring 3|k and hold the inlet port 3| i normally open. When theroller 3| 0 engages the cam track I8 the arm 3|n is rocked therebyrelieving the tension of the spring 3|p holding the inlet port 3lf open.The port 3|f is then closed by the compression spring 3|7c and at thesame time the relief port 3| g is opened.

The valves 3|, 32 and 33 all have a similar construction and operate inthe same manner.

The mechanism is shown in a position ready to start a forming operationin Figs. 1 and 10, in which the metal plate 43 to be formed is locatedon the top of the female die member 4. As the head I descendsdownwardly, an annular shearing edge 44, which forms part of an annularmember 45, trims off the edges of the metal. Prior to the actual formingof the metal plate, the lower cylinder head 46 bears frictionallyagainst the surface 43 of the sheet outside that which covers theopening 1, the pressure down wardly being controlled by the regulatingvalve 3|b and as stated, usually ranging from 60 to 100 lbs.

The frictional clamping of the lower surface of the head 46 ismaintained against the metal by the air pressure in the compressioncylinder A. This same pressure, until released, holds the head 22 backagainst the latch 31.

The first stage ofthe forming occurs when the head moves sufficientlyfar down to cause the male dies 24, 25 and 26 to be depressed within thefirst stage forming chamber, as indicated in Fig. 3. During thisdownward movement of the head carrying the telescoping male dies, thefrictional retainment of the area of the sheet 43 around the die chamberopening caused by the air pressure in the cylinder A,- is sufiicient topermit the metal to be evenly drawn down into the first stage diechamber. When this stage is reached, the arm 34, which controls the airto the compression cylinder A is cut off and exhausted from the cylinderby contact with the cam track l8, as indicated in Fig. 3.

The second and third forming operations are carried out in a similarmanner, and since the illustration in Fig. 4 shows the parts in theposition after the third forming operation, this operation only will bedescribed. It will be noted that during the second forming operation,the outwardly beveled lower edge of a the male die 24 frictionallyclamps and retards the passage of the metal by engaging the formed sheetbetween its outwardly beveled edge and the inwardly extending annularledge 8 of the female 'die.

Prior to the start of the third forming operation, the outwardly flaringlower edge of the male die 25 will bear against the inwardly inclinedshoulder ill of the second stage die chamher. This will permit the metalto be drawn down in the third forming operation, so that it will flowevenly. The compression chamber C holds the die 25 in position duringthe third forming operation.

As the die- 26 reaches the lower limit of its stroke and before the airfrom the cylinder C has been cut of! and exhausted, the ram 21 descendswithin the female die l3 and completes the final forming of the metal.The head I is then moved upwardly, as illustrated, withdrawing the ramand male dies and an upward stroke of the ram l5, causes the ejection ofthe formed metal object in its final form.

During the operation the frictional clamping due to the pneumaticpressure causes suflicient heat to bring about an even flow of metal inthe drawing operation. r

In Figs. 6 to 9 the form of the metal after each operation is shown.In'Fig. 6, the metal sheet 43 has been formed as shown at "a. This isthe form of the metal after the first forming operation with the partsof the mechanism as shown in Fig. 3.. In Fig. 'I the metal is formed asindicated at "b. In Fig. 8 the metal is formed as indicated at c. If theparts illustrated in Fig. 4 were to be moved upwardly and the metalcontainer were to be withdrawn from the female die chamber I I it wouldhave the form illustrated at "c in Fig. 8. The final form of thecontainer is shown at "at in Fig. 9.

I have illustrated the forming of a metal container of rectangularshape, this being one of the more diificult shapes to form but it willbe apparent that by a change in shape of the dies other forms such assquare. octagonal, and round may be made.

In the claims which follow I do not limit the application of the formingoperation either to any particular shape or size nor do I limit itsapplication to a forming operation of any definite number of steps suchas the four forming steps described. Any multiple number of formingoperations may be accomplished by utilizing the pneumatic clampingprinciple involved, and by my arrangement I am able to so regulate theair pressure in the respective cylinders that the desired frictionalclamping pressure for successive draws may be obtained. Thus myarrangement provided for a nicety of drawing operations not possible inthe constant and uniform hold-down arrangement of Schimmelbusch in hisPatent No. 783,390.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. In sheet forming apparatus in which meta is formed, a female diehaving successive die chambers of decreasing cross dimensions and a maledie comprising a series of telescoping male die elements each fittingwithin a successive die chamber during a forming operation therein,pneumatic means which may be regulated to a difierent pressure for eachdie for retaining each of said telescoping male die elements infrictional clamping engagement with metal being formed during theforming operation in the next successive die chamber, said pneumaticmeans comprising a series of cylinder heads within compression cylinderseach cylinder head carrying a male die element, and means for releasingthe pneumatic pressure within said cylinders during successive stages ofthe forming operations.

2. Sheet forming apparatus comprising a female die having a series ofdie chambers formed therein of decreasing cross dimensions, a frictionalclamping member for retarding the metal of a sheet as it is drawn insaid die chamber, regulatable pneumatic means for actuating saidclamping member and a series of telescoping male dies for successivelyforming the metal of a sheet in said series of die chambers, said seriesof male dies being reciprocable through an opening in said clampingmember, and independently regulatable and pneumatic means for actuatingone of said male die members to cause it to effect a clamping pressureon a sheet being drawn during the reciprocation or another male diemember through said first noted male die member.

JAMES L. AUBLE.

